Expansion Joint Foam is a closed cell polyethylene foam, it can be used as a joint filler, joint former, grout check, non-load transfer filler, stop-end, insulant and more applications. It�s compressible yet semi-rigid, non-absorbent and strong. The foam is light, clean and very easy to use, it can be used on all normal building surfaces. It�s highly resistant to most site�chemicals and oils, with weathering and ozone resistance.